tests/language/runtime_type_function_test.dart

// Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import "package:expect/expect.dart";

typedef String F(String returns, String arguments);
F fn;

String form1(String returns, String arguments) => '$arguments => $returns';
String form2(String returns, String arguments) => '$returns Function$arguments';

F detectForm() {
  var s = main.runtimeType.toString();
  if (s.contains('=>')) return form1;
  if (s.contains('Function')) return form2;
  Expect.fail('"$s" contains neither "=>" nor "Function"');
}

main() {
  fn = detectForm();

  // Types that do not use class names - these can be checked on dart2js in
  // minified mode.

  check(fn('dynamic', '()'), main); //        Top-level tear-off.
  check(fn('void', '()'), Xyzzy.foo); //      Class static member tear-off.
  check(fn('void', '(dynamic)'), [].add); //  Instance tear-off.
  check(fn('dynamic', '()'), () => 1); //       closure.

  var s = new Xyzzy().runtimeType.toString();
  if (s.length <= 3) return; // dart2js --minify has minified names.

  Expect.equals('Xyzzy', s, 'runtime type of plain class prints as class name');

  check(fn('void', '(String, dynamic)'), check);

  // Class static member tear-offs.
  check(fn('String', '(String, [String, dynamic])'), Xyzzy.opt);
  check(fn('String', '(String, {String a, dynamic b})'), Xyzzy.nam);

  // Instance method tear-offs.
  check(fn('void', '(String)'), <String>[].add);
  check(fn('void', '(int)'), <int>[].add);

  check(fn('String', '(int)'), new G<String, int>().foo);

  // Instance method with function parameter.
  var string2int = fn('int', '(String)');
  check(fn('String', '($string2int)'), new G<String, int>().moo);

  // Closures.
  String localFunc(String a, String b) => a + b;
  void localFunc2(int a) {
    print(a);
  }

  Expect.isTrue(localFunc is F);
  check(fn('String', '(String, String)'), localFunc);
  check(fn('void', '(int)'), localFunc2);
}

void check(String text, var thing) {
  var type = thing.runtimeType.toString();
  if (type == text) return;
  Expect.fail("""
Type print string does not match expectation
  Expected: '$text'
  Actual: '$type'
""");
}

class Xyzzy {
  static void foo() {}
  static String opt(String x, [String a, b]) {}
  static String nam(String x, {String a, b}) {}
}

class G<U, V> {
  U foo(V x) => null;
  U moo(V f(U x)) => null;
}